The present invention relates to single-tank dehydration-type agitator-operated washing machines, and more particularly to an improvement in a dehydrating tank stopping mechanism in such a single-tank dehydration-type agitator-operated washing machine.
First, a conventional single-tank dehydration-type washing machine will be described with reference to FIG. 1. As shown in FIG. 1, the washing machine includes a pulsator 20 and a dehydrating (spinning) tank 4 having the pulsator 20 at its center and a side wall is which a number of through-holes 5 are formed. A water holding tank 7 is provided outside the tank 4. The water holding tank 7 has a water discharging outlet (not shown) in its bottom. The water discharging outlet is connected to a drain pipe.
Further in FIG. 1, reference numeral 8 designates an electric motor, which is coupled to a rotation transmitting section 12 through a speed reducing mechanism composed of a pulley 9, a V-belt 10 and a pulley 10. The rotation transmitting section 12 has dual drive shafts 12a and 12b which are controlled by a spring clutch mechanism 13. The outer drive shaft 12a is coupled to the dehydrating tank 4 and the inner drive shaft 12b to the pulsator 20.
In a washing operation, the washing load (clothes), water and detergent are put into the dehydrating tank 4, and then the power switch is turned on. As a result, the motor 8 is rotated, and accordingly the pulsator 20 is rotated. The washing operation continues for a predetermined period of time as set by a timer provided in the control device, and then the water is discharged. Thus, a washing operation has been accomplished.
Next, a dehydrating (spin cycle) operation is carried out. In the dehydrating operation, the spring clutch mechanism 13 is operated so that the shaft 12a is rotated together with the shaft 12b. Therefore, the dehydrating tank 4 and the pulsator 20 are rotated as a unit by the motor 8.
FIGS. 2 and 3 show a conventional mechanism for stopping the rotation of the dehydrating tank. A brake wheel 14 is fixedly mounted on the drive shaft 12a of the dehydrating tank 4, and a brake band 15 having a locking pawl 15a is passed around the brake wheel 14.
A brake lever 17 having a brake lever spring 16 is provided for the brake wheel 14. When the brake lever 17 is unlocked by means of a solenoid or the like, the locking part 18 provided at the end of the brake lever 17 is abutted against the brake band 15 by the elastic force of the spring 16. However, in this case, the locking part 18 of the lever 17 is not at first engaged with the locking pawl 15a of the brake band 15, and therefore the brake band 15 turns together with the brake wheel 14; that is, no braking operation is carried out yet. As the brake band 15 turns, the locking pawl 15a finally engages with the locking part 18, as a result of which the brake band 15 is stopped. Therefore, the rotation of the drive shaft 12a is stopped by the frictional force between the brake band 15 and the drive shaft 12a of the dehydrating tank 5, and accordingly the dehydrating tank 4 is stopped. In this case only the drive shaft 12b of the pulsator 20 is permitted to rotate (upon disengagement of clutch 13).
In the dehydrating operation, the lever 17 is moved away from the brake band 15 against the elastic force of the spring 16 by means of a solenoid or the like. As a result, the locking part 18 of the lever 17 is disengaged from the locking pawl 15a of the brake band 15, and therefore the drive shaft 12a of the dehydrating tank 4 is rotated together with the drive shaft 12b of the pulsator 20 at high speed.
To change between rotation of the shafts 12a and 12b as a unit and rotation of only the shaft 12b, the spring clutch mechanism 13 is operated. The construction of the spring clutch mechanism 13 will be described with reference to FIG. 3.
In FIG. 3, reference numeral 13a designates the clutch gear of the spring clutch mechanism 13. Simultaneously when the lever 17 starts the braking operation, the ratchet 19a at the end of the operating lever 19, which is integral with the brake lever 17, is engaged with the clutch gear 13a. With the gear 13a held fixed in this manner, the internal spring is released and the drive shafts 12a and 12b are disconnected from each other. As a result, only the drive shaft 12b is rotated; that is, only the pulsator 20 is rotated while the dehydrating tank 4 is maintained stopped.
The dehydrating tank stopping mechanism of a conventional single-tank dehydration-type pulsator-operated washing machine has been described above. The application of a spring clutch mechanism to an agitator-operated washing machine suffers from difficulties as will now be described.
FIG. 4 is a vertical sectional view of a single-tank dehydration type agitator-operated washing machine. In FIG. 4, those components which have been described with reference to FIG. 1 are designated by like reference numerals.
As is well known in the art, an agitator-type washing machine uses an agitator 1 instead of the pulsator 20. The agitator 1 turns through an angle smaller than 360.degree.. In general, the agitator 1 is rocked through about 240.degree. by alternately rotating the electric motor 8 in the forward and reverse directions.
When a braking operation is started by abutting the locking part 18 of the brake lever against a point (for instance, the point A in FIG. 5) on the brake band 15 which is more than 240.degree. away from the locking pawl 15a of the brake band 15, the locking part 18 will never reach the locking pawl 15a. That is, the locking part 18 will never engage the locking pawl 15a because the motor 8 is alternately rotated in the forward and reverse directions, and the drive shafts 12a and 12b and the brake wheel 14 are rocked through angles smaller than 240.degree. (angles smaller than angle A-B in FIG. 5, alternately in the forward and reverse directions). Accordingly, the dehydrating tank 4 is not braked, and can thus be driven by the agitator 1 through the medium of the clothes, etc. in the tank 4. As a result, no water eddy current is formed in the tank.